Automatic medicament ingredient mixing and injecting apparatus

ABSTRACT

An automatic injector apparatus comprising an outer housing assembly, a hypodermic needle, first and second containers, a first liquid medicament ingredient in the first container and a second medicament ingredient in the second container, first and second pistons in the first and second containers respectively, a releasable stressed spring arrangement capable of being released twice, once for movement through a first piston moving stroke and second through a second piston moving stroke, a first releasing device operable in response to a first predetermined actuating procedure for accomplishing a first release of the spring arrangement so as to effect movement of the first piston through a liquid medicament ingredient moving stroke causing the liquid medicament ingredient to mix with the medicament ingredient in the second container to form liquid medicament and a second releasing device operable in response to a second actuating procedure for accomplishing a second release of the spring arrangement so as to effect movement of the second piston through an operative stroke causing the hypodermic needle to be moved into the muscle tissue of the patient and the liquid medicament to be moved through the needle into the muscle tissue of the patient.

This is a division of application Ser. No. 735,995, filed May 20, 1985,now U.S. Pat. No. 4,689,042.

This invention relates to automatic injectors and more particularly toautomatic injectors of the type operated by the release of a stressedspring assembly.

Spring operated automatic injectors have been known for many years. Themost extensive use of automatic injectors of this type has been tocontain a chemical warfare antidote. Other uses of injectors of thistype include antidotes for bee stings and anti-arrhythmic medicaments,such as lidocaine. In recent years there have been proposed multi-dosageautomatic injectors. Such multi-dosage automatic injectors include thepackaging of two single dose injectors in one package, U.S. Pat. No.4,329,988 or providing a single device with a single actuating mechanismwith plural medicament cartridges, U.S. Pat. No. 4,226,235. Where theplural medicaments are in liquid form they can be packaged in a singlemedicament cartridge assembly for sequential injection by springactuation, see U.S. Pat. No. 4,394,863.

A problem with respect to the single cartridge type units is that theamount of liquid medicament that can be utilized is severely limited. Adisadvantage of the dual cartridge units is that they become quite bulkyand more difficult to handle. This is particularly true where fairlylarge amounts of liquid medicament must be injected.

The present invention is based upon the fundamental principal that thesetwo disadvantages of the prior art can best be accomodated by theprovision of an automatic injector assembly which in its storagecondition contains the medicament ingredients, at least one of which isin liquid form and then utilizing the automatic spring function providedto mix the medicament ingredients to form liquid medicament and then toinject the liquid medicament.

The patented prior art contains disclosures of many manually operablesyringes capable of containing a plurality of separate medicamentingredients and of subsequently mixing and injecting the same. Examplesof prior art of this type include U.S. Pat. Nos. 2,591,046, 3,326,215,3,464,412, 3,494,359, 4,059,109, 4,226,236, and 4,405,317.

While mixing type syringes have been known in the prior art for manyyears, applicant is unaware of any automatic spring actuated typeinjectors having the capability of first mixing a plurality ofseparately contained medicament ingredients and subsequently injectingthe same. In commonly assigned U.S. Pat. No. 3,451,393 there isdisclosed an automatic infusion device which includes a housing forreceiving a pair of side by side containers each of which contains aseparate medicament ingredient. Stressed spring assemblies areassociated with each of the two containers, one of which is releasableto accomplish the mixing procedure and the release of the other of whichserves to pressurize the mixture for use in the infusion process.

In view of the above, it is an object of the present invention toprovide an automatic injector device of the spring actuated type whichhas the capability of first mixing a plurality of separately containedmedicament ingredients and then effecting an automatic injection thereofinto the muscle tissue of a patient. This capability is highly desirablesince it accomplishes under emergency conditions an intramuscularinjection of a maximum amount of medicament in liquid form forabsorption into the blood so as to accomplish a desired therapeuticeffect.

In accordance with the principles of the present invention, the aboveobject is accomplished by providing an automatic injector apparatuscomprising an outer housing assembly, a hypodermic needle, first andsecond containers, a first liquid medicament ingredient in the firstcontainer and a second medicament ingredient in the second container,first and second pistons in the first and second containersrespectively, a releasable stressed spring arrangement capable of beingreleased twice, once for movement through a first piston moving strokeand second through a second piston moving stroke, a first releasingdevice operable in response to a first predetermined actuating procedurefor accomplishing a first release of the spring arrangement so as toeffect movement of the first piston through a liquid medicamentingredient moving stroke causing the liquid medicament ingredient to mixwith the medicament ingredient in the second container to form liquidmedicament and a second releasing device operable in response to asecond actuating procedure for accomplishing a second release of thespring arrangement so as to effect movement of the second piston throughan operative stroke causing the hypodermic needle to be moved into themuscle tissue of the patient and the liquid medicament to be movedthrough the needle into the muscle tissue of the patient.

Another object of the present invention is the provision of an automaticinjector or injecting apparatus capable of mixing a contained liquidmedicament ingredient and another medicament ingredient to form liquidmedicament and of subsequently injecting the liquid medicament, whichapparatus is simple in construction, effective in operation andeconomical to manufacutre.

These and other objects of the present invention will become moreapparent during the course of the following detailed description andappended claims.

The invention may best be understood with reference to the accompanyingdrawings wherein illustrative embodiments are shown.

In the drawings

FIG. 1 is a longitudinal sectional view of an automatic mixing andinjecting apparatus embodying the principles of the present inventionshowing the parts in their storage position;

FIG. 2 is a view similar to FIG. 1 showing the parts in their mixing orliquid medicamant forming position;

FIG. 3 is a view similar to FIG. 1 showing the parts in their finalinjecting position;

FIG. 4 is a sectional view taken along the line 4--4 of FIG. 1;

FIG. 5 is a view similar to FIG. 1 of another form of automatic mixingand injecting apparatus embodying the principles of the presentinvention;

FIG. 6 is a sectional view taken along the lines 6--6 of FIG. 5;

FIG. 7 is view similar to FIG. 1 of still another form of automaticmixing and injecting apparatus embodying the principles of the presentinvention;

FIG. 8 is a view similar to FIG. 2 of the apparatus shown in FIG. 7;

FIG. 9 is a view similar to FIG. 3 of the apparatus shown in FIG. 7;

FIG. 10 is a view similar to FIG. 1 of still another form of automaticmixing and injecting apparatus embodying the principles of the presentinvention;

FIG. 11 is a view similar to FIG. 2 of the apparatus shown in FIG. 10;

FIG. 12 is a view similar to FIG. 3 of the apparatus shown in FIG. 10,and

FIG. 13 is a sectional view taken along the lines 13--13 of FIG. 10.

Referring now more particularly to the drawings, there is shown in FIG.1 an automatic injector or mixing and injecting apparatus, generallyindicated at 10, which embodies the principles of the present invention.As shown, the apparatus 10 includes an outer housing assembly 12 havingan inner housing structure 14 mounted therein for rectilinear slidingmovement from a storage position, as shown in FIG. 1, forwardly into aninjecting position, as shown in FIG. 3. Inner housing structure 14 hasconnected thereto a hypodermic needle assembly 16. A first liquidmedicament ingredient container assembly 18 is operatively associatedwith the inner housing structure 14 and a side by side related secondmedicament ingredient container assembly 20 is likewise operativelyassociated with the inner housing structure 14. Operatively associatedwith the first and second container assemblies 18 and 20 are first andsecond stressed spring assemblies 22 and 24. The first stressed springassembly 22 is mounted in a stressed condition on the inner housingstructure 14 in operative relation with the first container assembly 18.The second stressed spring assembly 24 is connected with the outerhousing assembly 12 in a stressed condition in operative relation withthe second container assembly 20. A safety cap and releasing pinassembly 26 is mounted in operative relation with respect to the firstand second spring assemblies 22 and 24 for rendering the apparatusinoperable and for enabling the first spring assembly to be released inresponse to a first predetermined actuating procedure and the secondspring assembly to be released in response to a second actuatingprocedure.

As shown, the outer housing assembly 12 includes an elongated tubularhousing member 28 having an integral rear wall 30 and an open forwardend which has formed in the exterior periphery thereof an annular groove32. A forward housing member 34 includes a rearward annular skirt 36having an annular ridge 38 formed on the interior periphery thereof forcooperatively engaging within the annular groove 32 so as to secure thetwo housing members together. As shown, the housing member 34 alsoincludes a forwardly projecting centrally apertured skin contactingportion 40.

The inner housing structure 14 includes a tubular member 42 having aribbed exterior periphery which slidably engages the interior peripheryof the outer housing member 28. The inner housing member 42 alsoincludes a rear wall 44 and, like the outer housing member 28, itsforward end is open and has an annular groove 46 formed therein. Thistime the annular groove 46 is on the interior surface of the innerhousing member 42 rather than the outer surface thereof as with theouter housing member 28. Fixedly mounted within the open forward end ofthe inner housing member 42 is a forward inner housing member 48.

As shown, the inner housing member 48 includes an integral needleelement 50 extending forwardly from the central portion thereof whichconstitutes part of the hypodermic needle assembly 16. The needleassembly 16 also includes a resilient sheath 52 the forward end of whichengages within the central opening in the skin engaging portion 40 ofthe outer housing assembly 12. The tip of the resilient sheath 52 closesthe forward central aperture of the outer housing assembly 12 and sealsthe sharp piercing end of the needle element 50. The needle element 50is of the hypodermic type including an interior passage 54 for theconveyance of a liquid medicament outwardly thereof into the muscletissue of the patient. The rearward end of the needle passage 54connects with a cross passage 56 formed in the forward inner housingmember 48. As shown, one end of the cross passage 56 is plugged, asindicated at 58, and at a position spaced from the plug, the crosspassage 56 communicates with a first rearwardly extending passage 60which is formed in a first rearwardly projecting cylindrical portion 62having a rearwardly extending diaphragm piercing element 64 integraltherewith. The opposite end of the cross passage 56 connects with asecond rearwardly extending passage 66 formed in a second rearwardlyextending cylindrical portion 68 which terminates in a diaphragmpiercing element 70. It will be noted that the member 48 includes inaddition a rearwardly extending peripheral skirt 72 having an exteriorannular ridge 74 thereon which is adapted to cooperate with the annulargroove 46 to secure the forward inner housing member 48 with the tubularinner housing member 42.

The first and second container assemblies 18 and 20 include first andsecond containers 76 and 78 which, as shown, are formed of plasticmaterial although they may be formed of glass if desired. The first andsecond containers 76 and 78 are arranged to engage within a containersupport structure, generally indicated at 80. The container supportstructure 80 includes a peripheral wall 82 which includes exteriorsurfaces which engage with the interior periphery of the inner housingmember 42 for sliding movement with respect thereto from a storageposition, as shown in FIG. 1, to a mixing or liquid medicament formingpostion, as shown in FIG. 2. The container support structure 80 includesa first bore 84 which extends forwardly from the rearward end thereofand terminates in an annular shoulder 86 so as to receive the firstcontainer 76 forwardly therein. The first container is formed by acylindrical wall which is open at its rearward end and which has anexteriorly flanged necked down forward end, indicated at 88. A piercablediaphragm 90 is mounted on the forward end of the exteriorly flangednecked down end 88 and is retained thereon by a hub assembly 92 whichincludes a rearward portion extending over the exterior annular flangeof the container and a forward portion of reduced diameter whichslidably sealingly engages the associated rearwardly projectingcylindrical portion 62 of the inner housing member 48.

The container support structure 80 also includes a second cylindricalbore 94 which extends rearwardly from the forward end thereof andterminates in a rearward inwardly directed annular shoulder 96 so as toreceive the second container 78 rearwardly therein. The second container78 is similar to the first and includes an open rear end and anexteriorly flanged necked down open forward end 98 which is closed by apiercable diaphragm 100 retained thereon by hub assembly 102 having arearward portion fixed to the exterior flange and a forward portion ofreduced diameter slidably sealingly engaging the associated rearwardlyextending cylindrical portion 68.

Mounted within the first container 76 is a liquid medicament ingredient104 which is sealed at its forward end by the associated piercablediaphragm and at its rearward end by a piston 106 formed of resilientmaterial which is slidably sealingly mounted within the rearwardinterior end portion of the container 76.

Similarly, the second container 78 has mounted therein a medicamentingredient 108 which, as shown, is in dry form and more specifically afreeze dried powder. Here again, the forward end of the medicamentingredient 108 is sealed by the associated diaphragm 100 and itsrearward end is sealed by a piston 110 which is constructed similarly tothe piston 106 previously described. Since, as shown, the second piston110 is disposed near the forward end portion of the second container 78in its storage condition, the remaining portion of the second containerdisposed rearwardly of the piston 110 desirably should be maintained ina sterile condition since it is to receive liquid medicament when thesecond piston 110 is moved rearwardly from its storage position to aposition enabling the liquid medicament to be moved forwardly. In orderto seal the rearward end of the second container 78 there is mountedtherein a sealing piston 112 which has venting slots 114 formed in theforward portion thereof.

The first stressed spring assembly 22 includes a hollow plunger 116 theforward end of which is flanged, as indicated at 118, and disposed inengagement with the first piston 106 forming a part of the firstcontainer assembly 18. The rearward portion of the plunger 116 isslotted, as indicated at 120, to form a plurality of annularly spacedresilient fingers 122 which are integral with the plunger. The fingers122 are formed with exterior plunger retaining surfaces 124 which faceforwardly and outwardly and extend at an angle of approximately 45° . Itwill be noted that the rearward end wall 44 of the inner housing member42 is apertured to receive the plunger and is provided with cooperatinginterior plunger retaining surfaces 126 which face inwardly andrearwardly and extend at an angle of approximately 45°. The fingers 122of the plunger 116 are also provided with a series of interior plungerreleasing surfaces 128. These surfaces are disposed within a commoncylindrical plane which has a diameter substantially less than theinterior diameter of the hollow plunger. The interior plunger releasingsurfaces extend from the rearward end of the fingers inwardly a shortdistance. Mounted within the interior plunger releasing surfaces 128 ofthe fingers 122 is a first releasing pin 130 which, as shown, forms apart of the safety cap and releasing assembly 26.

It will be understood that when the releasing pin 130 is disposed inengagement with the interior plunger releasing surfaces 128 theassociated fingers 122 are prevented from being deflected radiallyinwardly. The releasing pin 130 thus serves to insure that the exteriorplunger retaining surfaces 124 of the fingers 122 will be maintained inengagement with the cooperating plunger retaining surfaces 126 of theinner housing structure 14. This maintenance is provided notwithstandingthe bias which is present by virtue of a stressed coil spring 132forming a part of the spring assembly 22. Coil spring 132 is mountedover the exterior periphery of the plunger 116 with its forward end inengagement with the flange 118 and its rearward end in engagement withthe forwardly facing surface of the rearward end wall 44 of the innerhousing structure 14. In order to center the coil spring 132, preferablythe end wall 44 is provided with an integral forwardly extendingcylindrical skirt portion 134 which surrounds the rearward end portionof the coil spring 132.

The second stressed spring assembly 24 is similar to the first in thatit includes a hollow plunger 136 having a flange 138 on the forwardexterior periphery thereof and slots 140 formed in the rearward endportion thereof so as to define a series of annularly spaced radiallyinwardly deflectable spring fingers 142. As before, the spring fingers142 include exterior plunger retaining surfaces 144 and interior plungerreleasing surfaces 146. As shown, the rearward end wall 30 of the outerhousing member 28 is apertured to receive the second plunger 136 andincludes cooperating rearwardly and inwardly facing plunger retainingsurfaces 148. In this regard, it will be noted that the end wall 30 isalso apertured, as indicated at 150, to allow free movement of the firstplunger 116 therethrough. Similarly, the end wall 44 of the innerhousing member 42 is apertured, indicated at 152, to receive a forwardlyextending skirt 154 which surrounds the rearward end portion of astresed coil spring 156, the forward end of which engages the flange 138and the rearward end of which engages the forward surface of the endwall 30 of the outer housing member 28 surrounded by the skirt 154.

Mounted within the interior plunger releasing surfaces 146 of thefingers 142 of the second plunger 136 is a second releasing pin,generally indicated at 158. The releasing pin 158 is of the type adaptedto release the spring fingers 142 either when moved forwardly orrearwardly with respect to the rear end of the associated springfingers. As shown, the releasing pin 158 includes a forward movementpreventing portion 160 which has a diameter sufficient to engage withthe interior plunger releasing surfaces 146 so as to be disposed inengagement therewith when the plunger 136 is in its storage position.The releasing pin 158 also includes an actuating button 162 spacedrearwardly from the movement preventing portion 160 and movableforwardly to move the latter out of its storage position into areleasing position or movable rearwardly to remove the movementpreventing portion 160 from its storage position. To enable the forwardreleasing function to take place, the releasing pin 158 includes amovement preventing portion 164 of reduced diameter fixed between themovement preventing portion 160 and the actuating button 162.

In addition to the releasing pins 130 and 158, the assembly 26 alsoincludes a safety cap 166 which is formed as an end wall having anannular skirt extending forwardly thereof. The forward end of the skirtis recessed so as to engage over the rearward end portion of the outerhousing member 28 and to provide an annular shoulder 168 which engagesthe marginal peripheral portion of the rear wall 30. As shown, thereleasing pin 130 is detachably fixed with the end wall of the safetycap 166, as by a screw 170.

The apparatus 10 is assembled by first assembling the first stressedspring assembly 22 in operative relation with the end wall 44 of theinner housing member 42. This is accomplished by moving the plunger 116rearwardly within the inner housing member 42 until the rearward end ofthe plunger fingers 122 engaged through the opening defined by theplunger retaining surfaces 126. The releasing pin 130 is then insertedwithin the fingers 122 to prevent them from moving radially inwardly. Inthis way the plunger 116 is prevented from moving forwardly by virtue ofthe intergagement between the plunger retaining surfaces 124 and 126thus retaining the coil spring 132 in its stressed condition. Similarly,the second stressed spring assembly 24 is mounted in operative relationwith respect to the outer housing member 28 utilizing releasable pin158. Next, the safety cap 166 is engaged into its storage position andscrew 170 is threaded into secured relation within the releasing pin 130so that the latter will be moved out of its storage position in responseto the rearward movement of the safety cap 166 out of its storageposition, as shown in FIG. 1.

Next, the containers 76 and 78 are separately filled with the respectivemedicament ingredients 104 and 108 and sealed with the diaphragms 90 and100 by the hub assemblies 92 and 102 at their forward ends and with thepistons 106 and 110-112 at their rearward ends. Next, the two containersare mounted within the container support structure 80 and then the hubassemblies 92 and 102 are moved into an initial position with respect tothe cylindrical portions 62 and 68 of the member 48. After the resilientsheath 52 has been mounted over the needle element 50 the entire unitcontaining the two container assemblies 18 and 20, the inner housingstructure 14 and needle assembly 16 is moved rearwardly into the outertubular housing member 28 and the forward housing member 36 is snappedover the forward end thereof to complete the assembly.

To operate the apparatus 10 the operator first moves the safety cap 166out of its storage position, as shown in FIG. 1. This movementpreferably is accomplished by simply pulling the cap 166 off of itsengagement with the outer housing member 28. The removing of the safetycap 166 carries with it the safety pin 130 and this movement constitutesthe first predetermined actuating movement which effects the release ofthe first stressed spring assembly 22. In this regard, it will be notedthat the angle of the plunger movement preventing surfaces 124 and 126are such that as soon as the releasing pin 130 is removed from itsstorage position, the stress of the spring 132 will effect sufficientforward movement of the plunger 116 to cause the spring fingers 122 tobe moved radially inwardly until the surfaces 124 disengage from thesurfaces 126 and then the stressed spring 132 is capable of advancingthe plunger 116 forwardly through an operative stroke. Since the flange118 of the forward end of the plunger 116 is in engagement with thepiston 106 which in turn is in engagement with the liquid medicamentingredient 104 within the container 76, the initial forward movement ofthe plunger 116 will result in a forward movement of the entirecontainer 76 and the container support structure 80 by virtue of theengagement of the forward shoulder 86 thereof with the container 76.Similarly, this forward movement of the container support structure 80has the effect of moving the second container 78 forwardly by virtue ofthe rearward flange 96.

Thus, the initial movement of the plunger 116 results in a forwardmovement of both containers 76 and 78 and the container supportstructure 80. During this forward movement, the hub assemblies 92 and102 telescope with respect to the cyclindrical portions 62 and 68allowing the associated diaphragms 90 and 100 to move fowardly inpiercing relation to the associated piercing elements 64 and 70. Forwardmovement of the two containers and container support structure togetheris positively limited by the engagement of the forward end of the hubportions 92 and 102 with the rear surface of the inner housing member 48which in turn is held against forward movement by the engagement of theneedle assembly 16 with the outer housing assembly 12. When thediaphragms 90 and 100 are pierced, the interior of the two containers 76and 78 are communicated with each other through passage 60, crosspassage 56 and passage 66. Consequently, further forward movement of theplunger 116 under the action of the released stressed spring 132 resultsin the forward movement of the piston 106 within container 76 which hasthe effect of expelling the liquid medicament ingredient 104 from thecontainer 76 into the second container 78 so as to mix with themedicament ingredients 104 and 108 contained therein to form liquidmedicament and effect a rearward movement of the piston 110.

It will be noted that because the second stressed spring assembly 24 isretained in operative postion with respect to the outer housing assembly12, the flanged end 138 of the second plunger 136 assumes a positionrearwardly of the second container 78 by virtue of the aforesaid forwardmovement of the second container 78 with the container support structure80 during the initial movement of the first plunger 116. Consequently,as the forward piston 110 moves rearwardly, the air trapped between theforward piston 110 and the vent piston 112 tends to increase in pressurethus causing the vent piston 112 to be moved rearwardly into a positionof engagement with the flanged end 138 of the second plunger 136. Whenthe vent piston 112 is in such an engagement, the vent slots 114 ventthe interior space of the container 78 rearwardly of the piston 110 toatmosphere thus enabling the same to move rearwardly as the liquidmedicament ingredient from the first container flows into the secondcontainer. As best shown in FIG. 2, at the end of the operative strokeof the first plunger 116, substantially the entire amount of liquidmedicament ingredient 104 within the first container 76 has beentransferred into the second container 78 and mixed with the powdermedicament ingredient 108 therein to form liquid medicament.

It may be recommended that the operator at that point actually shake theapparatus 10 to insure that all the mixing of the medicament ingredientshas taken place to form liquid medicament to be injected. Injection isaccomplished in response to a second predetermined actuating procedurewhich includes the operator gripping the exterior periphery of the outerhousing member 28 and moving the nose portion 40 into engagement withthe patient's skin in the area which is to receive the injection, as forexample, the thigh. Next, the operator simply pushes forwardly on theactuating button 162, as with the thumb, which has the effect ofreleasing the second stressed spring assembly 24. As before, themovement of the releasing pin 158 out of its storage position permitsthe stressed spring 156 biasing the plunger 136 forwardly to effect aradially inward movement of the plunger fingers 142 by virtue of theinterengagement between the plunger retaining surfaces 144 and 148. Asthe plunger 136 moves forwardly under the action of the releasedstressed spring 156 the forward flanged end 138 of the plunger 136 inengagement with the vent piston 112 tends to move the latter forwardlywhich in turn is in engagement with the piston 110 acting on the rearend of the liquid medicament within the container 78. The initialmovement of the plunger therefore applies a force to the liquidmedicament which tends to cause the same to move outwardly of the secondcontainer and into the passage 66. While the liquid medicament may movethrough the cross passage 56 and rearwardly into the passage 60 into thefirst container 76, this flow path is greatly restricted due to theresidual spring force acting on the first piston 106 by the releasedfirst spring 132. The resistance to flow outwardly of the passage 54through the needle element 50 is prevented by virtue of the blockage ofthe forward end of the passage 54 by the resilient sheath 52. Theresistance to the movement of the sharpened forward end of the needleelement 50 and the entire inner housing assembly 14 including the twocontainer assemblies 18 and 20 carried thereby is less than thehydraulic resistance and consequently, the applicaton of the force ofspring 156 through the plunger 136, pistons 112 and 110 to the liquidmedicament in the second container 78 is transmitted to the innerhousing assembly 14 through the engagement of the hub assemblies 92 and102 with the member 48, results in the movement of the needle element 50forwardly through the resilient sheath 52 and outwardly of the outerhousing portion 40 into the muscle tissue of the patient.

The forward movement of the inner housing assembly 14 with respect tothe outer housing assembly 12 is arrested by virtue of the compressionof the resilient sheath 52. When the forward movement of the innerhousing structure 14 is arrested by the compression of the sheath,continued forward movement of the plunger 136 under the bias of thespring 156 serves to advance the two pistons 112 and 110 within thecontainer 78 thus expelling the liquid medicament therein outwardlythrough the passage 66, the cross passage 56 and the passage 54 in theneedle element 50 into the muscle tissue of the patient. In this way,substantially the entire amount of the liquid medicament within thesecond container 78 is injected into the muscle tissue of the patient,as shown in FIG. 3. As soon as the injection has been completed theoperator simply withdraws the needle element 50 from the patient.

Referring now more particularly to FIGS. 5 and 6 of the drawings, thereis shown therein another form of apparatus, generally indicated at 210which embodies the principals of the present invention. The apparatus210 is similar to the apparatus 10 except that the containers are fixedwith respect to the inner housing structure and the safety cap and thereleasing assembly is of a different form.

As shown, the apparatus 210 includes an outer housing assembly 212, aninner housing structure 214 mounted within the outer housing assemblyfor movement forwardly from a storage position into an injectingposition. A hypodermic needle assembly 216 is fixed to the forwardcentral portion of the inner housing structure 214 within the outerhousing assembly 212 in a sterile condition disposed in a storageposition when the inner housing structure 214 is in its storage positonand capable of moving outwardly of the outer housing assembly 212 withthe inner housing structure 214 for movement into the muscle tissue of apatient when the inner housing structure moves into its injectingposition.

Embodied within the inner housing structure 214 is a first medicamentcontainer assembly 218 and a side-by-side second medicament containerassembly, generally indicated at 220. Operatively associated with thefirst medicament container assembly 218 and with the inner housingstructure 214 is a first stressed spring assembly, generally indicatedat 222. A second stressed spring assembly 224 is operatively connectedwith the second medicament container assembly 220 and with the outerhousing assembly 212. As before, a safety cap and releasing assembly,generally indicated at 226, is provided in a storage position forrendering the first and second stressed spring assemblies 222 and 224incapable of being released. When moved out of its storage position theassembly 226 enables the first stressed spring assembly 222 to bereleased in response to a first predetermined actuating procedure andthen the second stressed spring assembly 224 to be released in responseto a second predetermined actuating procedure.

The outer housing assembly 212 is similar to the outer housing assembly12 previously described in that it includes a main tubular outer housingmember 228 having a rear end wall 230 at its rearward end and being openat its forward end. The forward end is closed by a forward housingmember 232 which includes a rearwardly extending annular skirt having aninterior annular ridge formed therein for engaging within a cooperatingannular groove formed in the periphery of the forward end portion of theouter housing member 228. The forward outer housing member 232 alsoincludes a forwardly projecting skin engaging nose portion 234 which iscentrally apertured to permit movement of a needle 236 therethroughforming a part of the needle assembly 216.

The inner housing structure 214 includes an inner tubular housing member238 having an exterior peripheral configuration to slidably engagewithin the interior peripheral configuration of the outer housing member228. The inner housing member includes an end wall 240 at its rearwardend and, like the outer housing member 228 is open at its forward end.The inner housing structure 214 includes an inner housing member 242which provides a forward wall having an exterior annular ridge forengaging within an interior peripheral groove formed on the forward endportion of the inner housing member 242. The inner housing member 242also includes a rearwardly extending portion defining a first container244 extending rearwardly within the housing member 234 and a secondcontainer 246 in side-by-side relation with respect to the firstcontainer 244.

It will be noted that the hypodermic needle is of conventional metalconfiguration having a sharpened forward edge which is engaged withinthe tip of a resilient sheath 248 so as to close off communication ofthe hollow interior thereof. The rearward end of the needle communicateswith a rearwardly extending passage 250 which is formed in the centralforward portion of the inner housing member 242. The rearward end of thepassage 250 communicates with the intermediate portion of a crosspassage 252, one end of which communicates with the forward end of apassage 254 extending rearwardly in communication with the interior ofthe first container 244. The first container 244 includes therein aliquid medicament ingredient 256 which is sealingly confined rearwardlyby a piston 258 of suitable resilient material so as to be slidablysealingly mounted within the container 244.

The opposite end of the cross passage 252 communicates with acounterbore 260 formed in the forward portion of the member 242. The endof the counterbore 260 is closed by a detachable plug 262. Mountedwithin the counterbore 260 is a piston valve 264 which, as shown in FIG.5, is disposed in a storage position closing off communication betweenthe associated end of the cross passage 252 and a short passage 266extending from the counterbore rearwardly into communication with thesecond container 246. Mounted within the forward end portion of thesecond container 246 is a medicament ingredient 268 which preferably isin dry form, specifically a freeze dried powder. The medicamentingredient 268 is sealingly retained within the second container by apiston 270 which is of suitable resilient material like the piston 258previously described. Mounted in the rearward end portion of the secondcontainer 246 in rearwardly spaced relation to the forward piston 270 isa vent piston 272. The vent piston 272 is normally disposed in a storageposition spaced inwardly from the rearward end of the second container246. Formed in the interior periphery of the rearward end portion of thesecond container 246 is a plurality of annularly spaced vent grooves 274which extend from the rearward end portion of the piston 272 to therearward end of the second container 246.

The first stressed spring assembly 222 includes a hollow plunger 276 theforward end of which is flanged, as indicated at 278, and disposed inengagement with the first piston 258 forming a part of the firstcontainer 218. The rearward portion of the plunger 276 is slotted, asindicated at 280, to form a plurality of annularly spaced resilientfingers 282 which are integral with the plunger. The fingers 282 areformed with exterior plunger retaining surfaces 284 which face forwardlyand outwardly and extend at an angle of approximately 45°. It will benoted that the rearward end wall 240 of the inner housing member 238 isapertured to receive the plunger 276 and is provided with cooperatinginterior plunger retaining surfaces 286 which face inwardly andrearwardly and extend at an angle of approximately 45°. The fingers 282of the plunger 276 are also provided with a series of interior plungerreleasing surfaces 288. These surfaces are disposed within a commoncylindrical plane which has a diameter substantially less than theinterior diameter of the hollow piston. The interior plunger releasingsurfaces 288 extend from the rearward end of the fingers inwardly ashort distance. Mounted within the interior plunger releasing surfaces288 of the fingers 282 is a first releasing pin 290 which, as shown,forms a part of the safety cap and releasing assembly 226.

It will be understood that when the releasing pin 290 is disposed inengagement with the interior plunger releasing surfaces 288 theassociated fingers 282 are prevented from being deflected radiallyinwardly. The releasing pin 290 thus serves to insure that the exteriorplunger retaining surfaces 284 of the fingers 282 will be maintained inengagement with the cooperating plunger retaining surfaces of the innerhousing structure 214. This maintainance is provided notwithstanding thebias which is present by virtue of a stressed coil spring 292 forming apart of the spring assembly 222. Coil spring 292 is mounted over theexterior periphery of the plunger 276 with its forward end in engagementwith the flange 278 and its rearward end in engagement with theforwardly facing surface of the rearward end wall 240 of the innerhousing structure 214. In order to center the coil spring 292,preferably the end wall 240 is provided with an integral forwardlyextending cylindrical skirt portion 294 which surrounds the rearward endportion of the coil spring 292.

The second stressed spring assembly 224 is similar to the first in thatit includes a hollow plunger 296 having a flange 298 on the forwardexterior periphery thereof and slots 300 formed in the rearward endportion thereof so as to define a series of annularly spaced radiallyinwardly deflectable spring fingers 302. As before, the spring fingers302 include exterior plunger retaining surfaces 304 and interior plungerreleasing surfaces 306. As shown, the rearward end wall 320 of the outerhousing member 228 is apertured to receive the second plunger 296 andincludes cooperating rearwardly and inwardly facing plunger retainingsurfaces 308. In this regard, it will be noted that the end wall 230 isalso apertured to allow free movement of the first plunger 276therethrough. Similarly, the end wall 240 of the inner housing member238 is apertured to receive a forwardly extending skirt 309 whichsurrounds the rearward end portion of a stressed coil spring 310, theforward end of which engages the flange 298 and the rearward end ofwhich engages the forward surface of the end wall 230 of the outerhousing member 228 surrounded by the skirt 309.

Mounted within the interior plunger releasing surfaces 306 of thefingers 302 of the second plunger 296 is a second releasing pin,generally indicated at 312. The releasing pin 312 is of the type adaptedto release the spring fingers 302 either when moved forwardly orrearwardly with respect to the rear end of the associated springfingers. As shown, the releasing pin 312 includes a forward movementpreventing portion 314 which has a diameter sufficient to engage withthe interior plunger releasing surfaces 306 so as to be disposed inengagement therewith when the plunger 296 is in its storage position.The releasing pin 312 also includes an actuating button 316 spacedrearwardly from the movement portion 314 and movable forwardly to movethe latter out of its storage position into a releasing position ormovable rearwardly to remove the movement preventing portion 314 fromits storage position. To enable the forward releasing function to takeplace, the releasing pin 312 includes a movement enabling portion 318 ofreduced diameter fixed between the movement preventing portion 314 andthe actuating button 316.

In addition to the releasing pins 290 and 312, the assembly 226 alsoincludes a safety key 320 and a safety cap 322 which is formed as an endwall having a manually engagable annular skirt 324 extending forwardlythereof over a substantial portion of the outer housing member 228. Thekey 320 is in the form of a rearward wall which is integrally connectedwith the rear end of the pin 290. The key 320 also includes acylindrical wall portion 326 extending forwardly from the rear wall anda keyed or dual lug shaped wall portion 328 extending forwardly from theportion 326. Formed in the rear wall of the safety cap 322 is a keyed ordual lug shaped opening 330 of a size to receive the keyed portion 328therethrough which is rotationally aligned therewith. It will be notedhowever that when the safety key 320 is turned into the storage positionshown so as to be rotationally out of alignment, the keyed portion 328extends between the cap end wall and the outer housing member end wallso as to prevent forward movement of the cap 322 out of its storageposition as shown.

The apparatus 210 is assembled by first assembling the first stressedspring assembly 222 in operative relation with the end wall 240 of theinner housing member 238. This is accomplished by moving the plunger 276rearwardly within the inner housing member 238 until the rearward end ofthe plunger fingers 282 engage through the opening defined by theplunger retaining surfaces 286. The releasing pin 290 carried by thesafety key 320 is then inserted within the fingers 282 to prevent themfrom moving radially inwardly. In this way the plunger 276 is preventedfrom moving forwardly by virtue of the interengagement between theplunger retaining surfaces 284 and 286 thus retaining the coil spring292 in its stressed condition. Similarly, the second stressed springassembly 224 is mounted in operative relation with respect to the outerhousing member 228 utilizing releasable pin 312. Next, the safety cap322 is engaged into its storage position with skirt 324 extending overthe outer housing member 228 and with the opening 330 receiving theportion 326 of the key 320. Forward movement of the cap is stopped bythe engagement of the keyed portion 328 of the safety key 320 betweenthe cap rear wall and the housing member rear wall.

Next, the containers 244 and 246 are separately filled with therespective medicament ingredients 256 and 268 and sealed by the pistonvalve 266 and plug 262 at their forward ends and with the pistons 258and 270-272 at their rearward ends. Next, the housing member 242defining the two containers is mounted within the inner housing member238 and needle 236 is mounted in place. After the resilient sheath 248has been mounted over the needle 236, the entire unit containing the twocontainer assemblies 218 and 220, the inner housing structure 214 andneedle assembly 216 is moved rearwardly into the outer tubular housingmember 228 and the housing member 232 is snapped over the forward endthereof to complete the assembly.

To operate the apparatus 210 the operator first turns the safety key 320and moves it rearwardly out of its storage position, as shown in FIG. 5.The removal of the safety key 320 carries with it the safety pin 290 andthis movement constitutes the first predetermined actuating procedurewhich effects the release of the first stressed spring assembly 222. Inthis regard, it will be noted that the angle of the plunger movementpreventing surfaces 284 and 286 are such that as soon as the releasingpin 290 is removed from its storage position, the stress of spring 292will effect sufficient forward movement of the plunger 276 to cause thespring fingers 282 to be moved radially inwardly until the surface 284disengages from the surface 286 and then the stressed spring 292 iscapable of advancing the plunger 276 forwardly through an operativestroke.

Since the forward flanged end 278 of the plunger 276 is in engagementwith piston 258 which in turn is in engagement with the liquidmedicament ingredient 256, the force of the released stressed spring 292serves to increase the pressure within the liquid medicament ingredient256. This pressure is transmitted to the inner housing member 242 andthe liquid within the passage 254 and cross passage 252 therein. Theforce required to effect movement of the piston valve 264 isconsiderably less than the force required to effect movement of theentire inner housing member 214 and consequently the piston valve 264will be moved into a position uncovering the passage 266 so as to allowthe pressurized liquid medicament ingredient 256 to pass into the secondcontainer 246 to mix with the medicament ingredient 268 therein. As theliquid medicament ingredient 256 flows into the second container 246piston 270 will be moved rearwardly. This movement in turn causes theair rearwardly of the piston to increase and this increase in pressurein turn builds up until it is sufficient to effect a rearward movementof the vent piston 272. The vent piston 272 moves rearwardly until itengages the forward flanged end 298 of the plunger 296. In this positionvent grooves 274 are communicated with the space within the secondcontainer 246 forwardly of the vent piston 272 thus exhausting thepressure to atmosphere and allowing the piston 270 to move freelyrearwardly in response to the flow of liquid mediqament ingredient 256from the first container into the second container. When this movementhas been completed by virtue of the movement of the piston 258 into itsforwardmost postion, the operator may at that time shake the apparatusto insure that the liquid medicament 256 will be mixed thoroughly withthe medicament ingredient 268 within the second container.

Next, the operator performs the second predetermined manual actuatingprocedure which has the effect of injecting the liquid medicament formedduring the mixing operation. The actuating procedure includes graspingthe skirt 324 of the safety cap 322 and moving the nose portion 234 ofthe outer housing assembly 212 into engagement with the skin of thepatient in the area which is to receive the injection, as for example,the thigh. Continued forward movement on the skirt 324 has the effect ofeffecting the forward movement of the latter with respect to the outerhousing assembly 212 during which movement the rear wall of the safetycap 226 will engage the actuating button 312 and move the same forwardlyuntil movement preventing portion 314 thereof is disengaged from themovement preventing surfaces 306 of the spring fingers. Immediatelythereafter the force of spring 310 and the inclination of the surfaces304 and 308 are such as to cause the plunger 296 to move forwardlydeforming the spring fingers 302 radially inwardly until surfaces 304are disengaged from the surfaces 308. Continued forward movement of theplunger 298 acts through vent piston 272, piston 270 and the liquidmedicament forwardly thereof to move the inner housing structure 214forwardly. During the initial forward movement of the inner housingstructure 214, needle 236 pierces through the end of the resilientsheath 248 and extends outwardly beyond the housing nose portion 234into the muscle tissue of the patient. This outward movement is arrestedby the compression of the resilient sheath 248 against the housingportion 234. As soon as the forward movement of the inner housingstructure 214 is arrested, continued forward movement of the plunger 296will result in an outward movement of the liquid medicament forward ofthe plunger 270 outwardly of the second container through passage 266,cross passage 252, passage 250 and into the hypodermic needle 236 andfinally outwardly into the muscle tissue of the patient. This movementof the liquid ingredient from the container 246 into the muscle tissueof the patient continues until the piston 270 reaches its forwardmostposition within the container. As soon as this injection procedure hasbeen accomplished, the operator simply removes the device from thepatient and in this fashion withdraws the needle from the muscle tissue.

Referring now more particularly to FIGS. 7 through 9, there is showntherein still another form of automatic injecting apparatus, generallyindicated at 410 which embodies the principles of the present invention.The apparatus 410 differs from the apparatus 10 and the apparatus 210previously described in that the injecting function is accomplished inaccordance with the structural and functional principles enunciated incommonly assigned U.S. Pat. No. 3,396,726, the disclosure of which ishereby incorporated by reference into the present specification. -Asshown, the apparatus 410 consists essentially of a plural cartridgeassembly, generally indicated at 412, a plural releasable stressedspring assembly, generally indicated at 414, and a safety cap andreleasing pin assembly, generally indicated at 416.

The plural cartridge assembly 412 includes a housing member 418 which isin the form of a molded plastic body providing a first cylindricalcavity 420 which is open at its rearward end and closed at its forwardend except for a central vent opening 422. The housing member 418 alsoprovides a second cylindrical cavity 424 which is open at its rearwardend and closed at its forward end except for a central opening 426.Formed in the portion of the housing member 418 defining the forward endportion of the first cavity 420 is a bore 428 which extends transverselythrough the periphery of the housing body radially inwardly into thecavity 420 and radially outwardly thereof into the second cavity 424 ata position spaced from the forward end thereof.

Mounted within the first cavity 420 is a piston valve 430 which in itsstorage position, shown in FIG. 7, extends forwardly and rearwardly ofthe bore 428 so that its forward surface is spaced from the forward endof the cavity 420. A plug 432 is formed in the outer portion of the bore428 so as to close off the same and prevent flow of liquid outward ofthe first cavity therethrough. The piston valve 430 which is molded of asuitable resilient material, as for example, an elastomeric resin orrubber, defines phe end of a medicament container within the housingmember 418 within which a liquid medicament ingredient 434 is contained.The rearward end of the liquid medicament ingredient 434 is confined bya piston 436 which, like the piston valve 430, is formed of a suitableresilient material. Detachably secured by the piston 436 and extendingrearwardly therefrom is a spacer 438 having its rearward end disposedadjacent the rearward open end of the first cavity 420.

Mounted in the forward end of the second cavity 424 in filling relationto the opening 426 is a piston or plug member 440 of resilient materialwithin which is received the sharpened end of a hypodermic needle 442,as by an inset fitting 444. The hypodermic needle 442 is hollow andincludes a lateral opening 446 in its rearward end portion and aflattened disk-like element 448 on its rearward end which is disposed inengagement with a piston 450 similar to the piston 436. The secondcavity 424, between the forward piston plug 440 and rearward piston 450,defines a second medicament container within which is mounted amedicament ingredient 452 preferably in the form of a dry powderalthough it may be in liquid form if desired. Mounted in the open rearend of the second cavity 424 is a disk shaped flap valve element 454which acts as a sterility check valve for the portion of the cavity 424between the valve element 454 and the piston 450.

The rearward exterior periphery of the housing member 418 is recessedand formed with an annular groove 456. The plural stressed springassembly 414 includes a housing member 458 which, like the housingmember 418, is in the form of a molded plastic body which includes aninteriorly ridged peripheral skirt 460 extending from the forward endthereof for engagement within the groove 456 as by a snap fit. The twohousing members 418 and 458 once assembled constitute an outer housingassembly of the apparatus 410.

The housing member 458 of the spring assembly 414 is formed with twocylindrical cavities 462 which are open at their forward ends andpartially closed at their rearward ends as by centrally apertured rearwall portions 464. The assembly 414 further includes components whichmake up two stressed spring assemblies similar to the stressed springassemblies 22 and 24 and 222 and 224 previously described. Thus each ofthe two stressed spring assemblies includes a plunger 466 having aflanged forward end 468 and a split rearward end portion definingradially inwardly deformable fingers 470 having exterior plungerretaining surfaces 472 and interior plunger releasing surfaces 474. Theapertured rear wall portions 464 are formed with corresponding plungerretaining surfaces 476 and a stressed coil spring 478 surrounds eachplunger 466 with its ends engaging the associated flanged forward end468 thereof and the associated rear wall portion 464.

Similarly, the safety cap and releasing pin assembly 416 is similar tothe assembly 226 previously described. As before, a safety key 480having an integral releasing pin 482 engageable with the releasingsurfaces 474 of the first plunger 466 is provided and a second releasingpin 484 similar to the releasing pin 312 previously described is mountedin operative relation with respect to the releasing surfaces 474 of thesecond plunger 466. Extending over the outer end portion of the rearwardhousing member 458 is a safety cap 486 which has a keyed opening forreceiving the safety key 480 and an elongated skirt 488 capable of beinggripped by the operator.

The assembly of the automatic injecting apparatus 410 will be readilyapparent in that the cartridge assembly 412 is assembled with thecomponents thereof being inserted forwardly into the cavities 420 and424 from the rear end thereof while the spring assemblies are assembledin the housing member 458 by moving the components rearwardly into theforward end of the cavaties 462. Once the releasing pins 482 and 484 arein place, the two housing members 418 and 458 are snapped together andthen the safety cap 486 is moved over the rear of the entire assembly.

The apparatus 410 is operated in a manner similar to the apparatus 210in that the first manual actuating procedure is to turn and remove thesafety key 480 which releases the first stressed spring 478. The releaseof the first spring accomplishes the mixing of the liquid medicamentingredient 434 with the powder medicament ingredient 452. The secondmanual actuating procedure is for the operator to grasp the elongatedsafety cap skirt 488 and move the forward end of the outer housingassembly into engagement with the skin of the patient at the locationwhere the injection is to take place. As a result of this actuatingprocedure the hypodermic needle 442 is extended into the muscle tissueof the patient and the liquid medicament which has previously beenformed is injected through the needle 442 into the muscle tissue of thepatient.

It will be noted that when the first stressed spring 478 is releasedfrom the storage position shown in FIG. 7 by the withdrawal of thesafety key 480 the force of the spring will be applied through spacer438 to the piston 436 which, in turn, is applied to the liquidmedicament ingredient 434 which, in turn, acts upon the piston valve430. The piston valve 430 therefore moves forwardly until it.engages theforward wall within which the vent aperture 422 is formed. When thepiston valve 430 reaches this position the inner portion of thecommunicating bore 428 serves to communicate the liquid medicamentingredient 434 with the cavity 424 within which the powder medicamentingredient 452 is mounted. As the liquid flows into this container, theair space within the container is compressed thus tending to move thepiston 450 rearwardly. As the piston 450 moves rearwardly the air withinthe space within the cavity 424 between the piston 450 and the flapvalve element 454 will increase slightly to a value which is sufficientto cause the flap valve element 454 to move rearwardly and communicatethe space rearwardly of the piston 450 with the atmosphere. In this way,the piston 450 is capable of being moved rearwardly into a position ofengagement with the forward end of the valve element 454 and the plungerend 468 without generating any air pressure acting in a direction tomove the piston 450 forwardly.

When the piston reaches its rearwardmost position, shown in FIG. 8,substantially all of the liquid medicament ingredient 434 has been movedinto the second container for mixing with the dry medicament ingredient452 therein. However, due to the initial presence of the air within thesecond container, an equivalent amount of air remains between theforward piston plug 440 and the rear piston 450, as shown in FIG. 8. Theexistence of this air within the cavity is essential to the properfunctioning of the apparatus 410 during the drive stroke of the secondplunger 466 when the second stressed spring 478 is released.

During the initial portion of the forward movement of the piston 450with the plunger 466 from the position shown in FIG. 8 the air withinthe second container will be compressed forwardly of the piston 450.Such air compression will continue to occur as the piston 450 movesforwardly until such time as the pressure reaches a value sufficient tocause flow of liquid out of the container through the bore 428 into thefirst cavity 420 moving the piston 436 back against the residual springpressure of the first spring 478. The arrangement is such that it ispreferable that when the piston 450 reaches the rear end of thehypodermic needle there will be a pocket of air forwardly of the pistonwhose axial dimension is equal to the distance the sharpened end of theneedle 442 must travel to enter within the muscle tissue of the patient.As previously indicated, the containment of such a volume of air mayrequire the outflow of liquid medicament from the second containerthrough the bore 428 into the first container.

When the piston 450 reaches the end of the hypodermic needle in theposition shown in FIG. 8, further forward movement of the piston 450will result in a forward movement of the hypodermic needle 442 with thepiston. In this way the needle 442 is moved into the muscle tissue ofthe patient and it will be noted that as the needle begins to move intothe muscle tissue of the patient the liquid medicament forwardly of thepiston also begins to flow into the needle opening 446 for passagetherethrough outwardly into the muscle tissue of the patient. When thepiston 450 reaches the forward end of its travel, as shown in FIG. 9, itis still possible for any liquid which may have moved into the firstcavity 420 in a position forwardly of the piston 436 to be movedoutwardly of the first cavity 420 through the bore 428 and finally intothe needle 442 and out into the muscle of the patient. As before, whenthe injection has been completed the operator simply removes theapparatus rearwardly which has the effect of removing the needle 442from the patient.

Referring now more particularly to FIGS. 10 through 13 there is showntherein still another form of an automatic injecting apparatus,generally indicated at 510, which embodies the principles of the presentinvention. The apparatus 510 exemplifies that the principles of thepresent invention can be carried out with only one stressed springassembly and with the medicament ingredient containers disposed inarrangements other than side by side. Specifically, in the apparatus 510the containers are telescopically mounted and it will be understood thatother arrangements can be utilized in practicing the principles of thepresent invention.

The apparatus 510 includes an outer housing assembly, generallyindicat.de at 512 within which is mounted a dual container cartridgeassembly 514 and a single stressed spring assembly 516. The apparatus510 also includes a safety cap and releasing pin assembly 518 which isoperable in response to a first predetermined manual actuating procedureto effect a first release of the stressed spring assembly 516 foreffecting the mixing function and a second releasing assembly 520operable in response to a second predetermined manual actuatingprocedure to effect a second release of the stressed spring assembly 516for effecting the injecting function.

As shown, the outer housing assembly 512 includes a tubular housingmember 522 in the form of a cylinder having an open forward end and arearward end closed by an end wall 524 having a central opening therein.The housing assembly 512 also includes a forward housing member 526which includes a rearwardly extending skirt 528 having a snap connectionover the exterior periphery of the forward end of tubular frame member522 and a central forwardly extending nose portion 530 which iscentrally apertured.

The dual container cartridge assembly 514 includes an outer container532 which is in the form of a cylindrical container open at its rearwardend and having a necked down exteriorly flanged forward end. A hubassembly 534 serves to connect the rear end of a hypodermic needle 536in communicating relation with the forward necked down end of thecontainer 532. A resilient sheath 538 is fixed over the hypodermicneedle 536 and its tip serves to sealingly retain liquid within thehypodermic needle 536 while in its storage condition and to retain thehypodermic needle in a sterile condition.

Mounted in the forward end of the outer container 532 is a medicamentingredient 540 preferably in the form of dry powder. The medicamentingredient 540 is confined at its rearward end by a large piston 542which has a deep recess 544 formed in the rear end portion thereof so asto define a thin forward central portion in the piston 542. Mountedwithin the outer container 532 rearwardly of the piston 542 is an innercontainer 546 which is of a configuration similar to the configurationof the container 532 but of smaller diameter. The necked down exteriorlyflanged forward end portion of the inner container 546 is connected, asby a hub assembly 548 to a short needlelike element 550, the sharpenedend of which is embedded within the central thin wall portion of thepiston 542 so as to provide a liquid seal thereof.

Mounted within the inner container 546 is a liquid medicament ingredient552 which is confined at its rear end by a piston 554 of resilientmaterial. As best shown in FIG. 10, there is a blowout ring seal 556provided in the rear end of the two containers 532 and 546 formaintaining the interior of the outer container 532 between the rearseal 556 and the piston 542 in a sterile condition when the apparatus510 is in its storage position, as shown in FIG. 10.

The stressed spring assembly 516 includes an elongated plunger 558having a flanged forward end 560 arranged to be disposed in engagementwith the piston 554 and an intermediate flange 562 for receiving one endof a stressed coil spring 564, the opposite end of which engages therear end wall 524 of the outer tubular housing member 522. The rear endportion of the plunger 558 is slotted to form a plurality of springfingers 566 which have plunger retaining surfaces 568 arranged to beengaged with a frustoconical plunger retaining surface 570 in the endwall 524 and interior plunger releasing surfaces 572 which, as shown inFIG. 10, engage the exterior of a releasing pin 574 forming a part ofthe assembly 518. As best shown in FIG. 10, the assembly 518 includes asafety cap 576 which is in the form of an end wall having a forwardlyextending skirt. The pin 574 is integral with the central forwardsurface of the cap end wall and the skirt is recessed to engage over theexterior periphery of the rear end of the tubular housing member 522 andto provide a shoulder 578 to limit the forward movement of the cap 576by engagement with the rear end wall 524.

The second releasing assembly 520 includes a manually engageable sleeve580 slidably frictionally mounted over the exterior periphery of theouter housing member 522. Formed in the forward end of the sleeve 580 isa slot 582 which registers with a smaller slot 584 formed in theperipheral wall of the tubular housing member 522. A releasing lock orbolt 586 is slidably mounted in the slots 582 and 584 and has an angularslot 588 formed therein within which a pin 590 extends. Pin 590 is fixedto the portion of the sleeve 580 defining slot 582, as is best shown inFIG. 13. The bolt 586 in its locking or storage position, as shown inFIG. 10, extends into the interior of the housing member 522 and engagesin front of an annular fitment 592 mounted forwardly of the outercontainer 546 at the position where it begins to neck down.

It will be understood that the apparatus 510 is assembled in much thesame manner as a conventional single dosage automatic injector of thetype disclosed in U.S. Pat. Nos. 3,882,863 and 4,031,893.

In operation, when it is desired to utilize the apparatus 510 theoperator first removes the safety cap 576 which has the effect ofwithdrawing releasing pin 574. As previously indicated, the angularrelationship between the plunger retaining surfaces 568 and 570 and thestrength of spring 564 is such that movement of the plunger 558commences in response to the withdrawal of the releasing pin 574. Assoon as the releasing pin 574 is no longer in engagement with theplunger releasing surfaces 572, the spring fingers 566 of the plunger558 are cammed radially inwardly so as to allow the plunger 558 to moveforwardly. The forward movement of the plunger is transmitted throughthe forward end 560 to the piston 554 which, in turn, is transmittedthrough the liquid medicament 552 to the inner container 546.Consequently, during the initial movement of the plunger 558 followingthe first predetermined manual actuating procedure of removing thesafety cap 576, the inner container 546 together with its hub assembly548 and needle 550 is moved forwardly. On the other hand, forwardmovement of the piston 542 is resisted by virtue of the presence of themedicament ingredient 540 forwardly thereof and consequently the needleelement 550 is pierced through the thin central portion of the piston542 so as to communicate the interior of the inner container 546 withthe interior of the outer container 532. As soon as this communicationtakes place the piston 542 and inner container member 546 are movedrearwardly as the liquid medicament ingredient 552 flows from the innercontainer into the outer container. Initially, blowout ring-shapedelements 556 are moved rearwardly out of sealing relation between theends of the inner and outer containers, allowing further rearwardmovement of the piston 542 within the outer container 532 to beaccomplished without an increase in the air pressure in the spacerearwardly of the piston 542 between the interior of the outer container532 and the exterior of the inner container 546. Because the pressurearea of the piston 542 is greater than the pressure area of the piston554 the flow of liquid from the inner container 546 into the outercontainer 532 will continue until such time as the piston 554 reachesthe forward end of the inner container 546. This position is shown inFIG. 11 and it will be noted that the spring 564 has expanded axiallyonly a small amount and hence considerable stress remains in the coilspring. This stress imposes a force upon the plunger 558 through theflange 562 which is transmitted through the piston 554, container 546,piston 542 and forwardly thereof to the outer container 532. Thecontainer 532 is prevented from moving forwardly under the bias of theinitially released spring 564 due to the engagement of the locking bolt586 with the fitment 592.

With the apparatus 510 in the position shown in FIG. 11, the operatorcan shake the unit to insure that the medicament ingredients arethoroughly mixed to form liquid medicament suitable to be injected.Injection is accomplished by the operator gripping the outer peripheryof the sleeve 580 and moving the nose portion 530 into engagement withthe skin of the patient in the area where the injection is to take placeas, for example, the thigh. As the operator applies a forward force tothe exterior of the sleeve 580 the pin 590 carried thereby is movedforwardly with respect to the outer housing member 522. This forwardmovement of the pin 590 by virtue of its engagement within the angularslot 588 causes the locking bolt 586 to move radially outwardly throughthe slots 584 and 582 into a position disposed out of engagement withthe fitment 592 as shown in FIG. 12. This movement then constitutes thesecond predetermined manual actuating procedure which effects a secondrelease of the stressed spring 564. This force which previously wasacting upon the outer container 532 to move the same forward now causesthis action to take place and the needle 536 moves outwardly of theresilient sheath 538 into the muscle tissue of the patient compressingthe sheath until its compression retards or stops the forward movementof the outer container 532. Further movement under the bias of spring564 results in the forward movement of the piston 542 within the outercontainer 532 until the piston reaches the forward end of the containerdischarging the last of the liquid medicament through the needle andinto the muscle tissue of the patient. As before, the operation iscompleted by the operator simply moving the device rearwardly whichcauses the needle 536 to withdraw from the patient's muscle tissue.

In all of the embodiments of the present invention illustrated includingthe apparatus 10, the apparatus 210, the apparatus 410 and the apparatus510, there is disclosed two separate medicament ingredients at least oneof which is a liquid medicament ingredient. The other medicamentingredient is preferably in dry form, specifically a freeze driedpowder, although it will be understood that the second liquid medicamentmay be in liquid form if desired. The liquid medicament which is formedin response to the first predetermined manual actuating procedure may beany desired liquid medicament. Examples are disclosed in my commonlyassigned U.S. application Ser. No. (735,311) filed concurrentlyherewith.

It thus will be seen that the objects of this invention have been fullyand effectively accomplished. It will be realized, however, that theforegoing preferred specific embodiment has been shown and described forthe purpose of illustrating the functional and structural principles ofthis invention and is subject to change without departure from suchprinciples. Therefore, this invention includes all modificationsencompassed within the spirit and scope of the following claims.

What is claimed is:
 1. In an automatic injector, including a medicamentcartridge assembly and a stressed spring assembly for operating saidmedicament cartridge assembly, the improvement which comprises saidstressed spring assembly comprisinga housing structure, an elongatedplunger having a plurality of annularly spaced elongated fingersconnected with the rearward end of said plunger for radially inwardovement from a plunger retaining position into a plunger releasingposition, said fingers having exterior plunger retaining surfaces onouter portions thereof and interior plunger releasing surfaces on innerportions thereof, spring means operatively connected between saidhousing structure and said plunger for movement from a storage positionin a releasably secured stressed condition through a forward plungermoving stroke in response to the release of the releasable securement ofthe stressed condition thereof, releasing means (1) disposed in astorage position in engagement with said interior plunger releasingsurfaces in radially inward movement preventing relation with respect tosaid fingers and (2) operable in response to a predetermined manualactuation procedure to be moved out of said storage position in radiallyinward movement enabling relation with respect to said fingers,cooperating plunger retaining surface means on said housing structureengaging said exterior plunger retaining surfaces for (1) retaining (a)said plunger against forward movement and (b) said spring means instressed condition when said releasable means is in said storageposition and (2) for enabling the stressed condition of said springmeans to effect (a) radially inward movement of said fingers and (b)forward movement of said plunger in response to the movement of saidreleasing means out of said storage position and the movement of saidspring means through said forward plunger moving stroke.
 2. Theimprovement as defined in claim 1 wherein said releasing means includesa releasing pin having a movement preventing portion disposed inengagement with the associated interior plunger retaining surfaces whensaid releasing pin is in a storage position, an actuating button spacedrearwardly from said movement preventing portion and movable forwardlyto move the latter out of its storage position and a movement enablingportion fixed between said movement preventing portion and saidactuating button for permitting radially inward movement of theassociated fingers when said actuating button is moved forwardly.
 3. Amethod of injecting a liquid medicament into the muscle tissue of apatient with the use of an automatic injector having therein ahypodermic needle, a releasable energy source and a plurality ofseparate medicament ingredients one of which is in powder form andanother of which is a liquid diluent for said powder ingredient, whichcomprises the steps ofperforming a manual actuating procedure withrespect to said automatic injector to thereby release energy from thereleasable energy source, utilizing energy released from the releasableenergy source as aforesaid to intermix said separate medicamentingredients within the automatic injector, dissolving the powderingredient in the liquid diluent so as to form injectable liquidmedicament from the intermixed ingredients, and utilizing furtherreleased energy of the releasable energy source to move the hypodermicneedle into the muscle tissue of the patient and the liquid medicamentformed as aforesaid through the hypodermic needle and into the muscletissue of the patient.
 4. A method as defined in claim 3 wherein thefurther released energy of the releasable energy source utilized in saidneedle and liquid medicament moving step is made available by a secondrelease of energy from said releasable energy source resulting from theperformance of a second manual actuating procedure.
 5. A method aasdefined in claim 4 wherein said automatic injector is manually agitatedafter the intermixing of the plurality of medicament ingredients andbefore the utilization of the further released energy to insure thatsaid dissolving step is completed.
 6. A method as defined in claim 5wherein said releasable energy source is in the form of stressed springmeans.
 7. A method as defined in claim 6 wherein said spring meanscomprises separate first and second stressed spring assemblies capableof being separately released.
 8. A method as defined in claim 6 whereinsaid spring means comprises a single stressed spring assembly capable ofbeing sequentially released.
 9. A method as defined in claim 6 whereinsaid intermixing step is performed by moving the liquid diluentingredient into an expansible container containing the powderingredient.
 10. A method as defined in claim 3 wherein said intermixingstep is performed by moving the liquid diluent ingredient into anexpansible container containing the powder ingredient.
 11. A method ofinjecting a liquid medicament into the muscle tissue of a patient withthe use of an automatic injector having therein a hypodermic needle, areleasable energy source and a plurality of separate medicamentingredients one of which is in powder form and another of which is aliquid diluent for said powder ingredient, which comprises the stepsofperforming successive first and second manual procedures in a timesequence closely following one another, causing as a reuslt of the firstmanual procedure the separate medicament ingredients within theautomatic injector to intermix to an extent sufficient to dissolve thepowder ingredient in the liquid diluent so as to form injectable liquidmedicament form the intermixed ingredients, causing as a reuslt of thesecond manual procedure the release of energy from the releasable energysource and utilizing the released energy source to move the hypodermicneedle into the muscle tissue of the patient and the liquid medicamentformed as aforesaid through the hypodermic needle and into the muscletissue of the patient.
 12. A method as defined in claim 11 wherein as aninitial result of the first manual procedure energy from the releasableenergy source is released and the released energy from said releasableenergy source is utilized to cause the intermixing of the separatemedicament ingredients.